Flow field characteristics in the near field region of particle-laden coaxial jets

The effects of solid particles on the flow structure in the near field region of a coaxial water jet are investigated non-intrusively using molecular tagging velocimetry. Glass beads of 240 μm and specific gravity SG of 2.46 are used at three volume loadings of γ_v=0.03, 0.06, and 0.09% in the central water jet with a Reynolds number of 4.1×10⁴. Measurements are acquired for four annular to central jet velocity ratios in the range 0.11≤ U _o/U _i≤1.15 at downstream distances up to six inner jet diameters and the results are analyzed for the effects of solid particles on the characteristics of flow. It is found that the addition of particles does not affect the mean fluid velocity profile in this region. The results also indicate a small and moderate enhancement of axial turbulent velocity and radial gradients of velocity fluctuations, respectively, due to the presence of particles.